…tion
This deprecation applies to:
`button_to`
`button_tag`
`image_submit_tag`
`link_to`
`submit_tag`
As :confirm is an UI specific option is better to use the data attributes,
teaching users about unobtrusive JavaScript and how Rails works with it.

* 3-2-stable-sec:
Strip [nil] from parameters hash. Thanks to Ben Murphy for reporting this!
predicate builder should not recurse for determining where columns. Thanks to Ben Murphy for reporting this
bumping to 3.2.4.rc1

railites_order method, introduced in 40b19e0, had a bug that was causing
loading application instance twice in initializers if railties_order
already included application instance. So for example
railties_order = [Foo::Engine, :main_app, Bar::Engine]
would result in such railties array:
[MyApp::Application, Foo::Engine, MyAppApplication, Bar::Engine]
In order to fix it, we need to check for existence of application in
both railties_order and railties arrays.

Using require in development mode will prevent required files from
reloading, even if they're changed. In order to keep namespaced
application_controller reloadable, we need to use require_dependency
instead of require.

In development mode, dependencies are loaded dynamically at runtime,
using `const_missing`. Because of that, when one of the constants is
already loaded and `const_missing` is not triggered, user can end up
with unexpected results.
Given such file in an Engine:
```ruby
module Blog
class PostsController < ApplicationController
end
end
```
If you load it first, before loading any application files, it will
correctly load `Blog::ApplicationController`, because second line will
hit `const_missing`. However if you load `ApplicationController` first,
the constant will be loaded already, `const_missing` hook will not be
fired and in result `PostsController` will inherit from
`ApplicationController` instead of `Blog::ApplicationController`.
Since it can't be fixed in `AS::Dependencies`, the easiest fix is to
just explicitly load application controller.
closes #6413